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Telephone Hearing Test Is a Valid Screening Tool, Study Shows

Hogan, Cynthia A. PhD

doi: 10.1097/01.HJ.0000470895.21812.d6
Journal Club

Dr. Hogan is a consultant in the Division of Audiology and director of the Hearing Aid Program at the Mayo Clinic.

Several months ago, I mentioned to a coworker that I thought I might have hearing loss. While I don't have difficulty in quiet, I have noticed increasing trouble hearing in noise. I am my own typical patient! My coworker told me I don't have hearing loss and not to worry about it. Working in a busy clinic, I still have not found time to check my own hearing. What about a quick screening? Maybe I can squeeze that in?

Clinical audiologists are challenged every day to see more patients more efficiently, while also bringing about excellent outcomes that can be documented. These demands can be handled in different ways, with screening tests serving as a conduit for getting the right patients to the right service provider.

We may find ourselves relying on mid-level providers such as audiology assistants to free us up for the tasks that require our education and skill set. Telemedicine and electronic consults are other means of providing services to those who may not otherwise have access to care. Patients are sometimes able to get a diagnosis or treatment recommendations without ever seeing a physician or specialist.

Hearing loss can go undiagnosed and untreated for many reasons, such as a perceived lack of problems, a low priority on a patient's list of health issues, and financial concerns. While the condition certainly is a quality-of-life issue, there usually are not concerns about life or death directly resulting from hearing loss.

Sometimes, hearing screening is a less intimidating way for people who have questions about their hearing to start addressing these concerns and, eventually, visit an audiology office when a full diagnostic evaluation is needed. Hearing screening might be completed in the nurse's office at school, or in a primary care, family medicine, or pediatric office.

There are now Internet hearing tests with hearing-in-noise options. Telephones and tablets are providing easier access to screening in the privacy of one's own home, without the full range of audiological test equipment.

The goal of any good screening program is to separate those who have a disease—hearing loss, in our case—and need a full evaluation (high sensitivity) from those who have normal results and don't need a full evaluation (high specificity). A good screening tool saves valuable time for the patient and clinical provider—and money for insurance companies—by cutting down on unnecessary testing.

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VALIDATING THE NHT

The National Hearing Test (NHT; J Am Acad Audiol 2012;23[10]:757-767 http://aaa.publisher.ingentaconnect.com/content/aaa/jaaa/2012/00000023/00000010/art00002) is a U.S. version of digit-sequence tests used in Europe. In the U.S. NHT, the eight single-syllable digits from one to nine serve as the stimuli.

The test uses a speech-shaped burst of noise with each three-digit sequence, varying the signal-to-noise ratio (SNR) to determine the threshold for 50-percent correct recognition. The test correlated with the three-frequency pure-tone average (PTA: 500 Hz, 1,000 Hz, and 2,000 Hz), but the relationship with Hearing in Noise Test (HINT) results was not as strong ( J Am Acad Audiol 2012;23[10]:757-767 http://aaa.publisher.ingentaconnect.com/content/aaa/jaaa/2012/00000023/00000010/art00002).

Validation of a Screening Test of Auditory Function Using the Telephone

Williams-Sanchez V, McArdle RA, Wilson RH, Kidd GR, Watson CS, Bourne AL

J Am Acad Audiol

2014;25(10):937-951 http://aaa.publisher.ingentaconnect.com/content/aaa/jaaa/2014/00000025/00000010/art00003

The goal of the study by Victoria Williams-Sanchez and colleagues was to validate the U.S. National Hearing Test in a large group of veterans from three Department of Veterans Affairs (VA) locations, investigating whether there was a correlation between audiological measures taken in clinical environments and NHT results completed on the telephone.

Pure-tone thresholds, Northwestern University Auditory Test No. 6 (NU-6) word-recognition scores in quiet, and speech-in-noise results from the Words-in-Noise (WIN) or the Quick Speech-in-Noise (QuickSIN) test were obtained for 693 veterans using insert earphones in a clinical setting.

All participants were then randomized into two groups: one group completed the National Hearing Test over the telephone at home, and the other group completed the NHT over the telephone at a VA clinic.

Analysis of three-frequency and four-frequency PTAs showed that participants from one site exhibited poorer hearing, which was attributed to their older age. The other two sites had more similar pure-tone averages.

In terms of the speech-recognition results in quiet and noise, there was a slight right-ear advantage for words in quiet (2.7%). In addition, the signal-to-noise ratio that resulted in a 50 percent recognition score on the QuickSIN test (mean of 10.9 dB SNR in the left ear and 11.5 dB SNR in the right ear) was approximately 1 dB to 2 dB better than the SNR observed for the WIN test (13.1 dB SNR in the left ear and 12.7 dB SNR in the right ear).

The authors used psychometric functions to compare results of the National Hearing Test with those of the WIN test, plotting percent correct as a function of SNR (dB). Participants were grouped and evaluated based on how well they did on the NHT.

Although the slope differed slightly between the two measures—it was steeper for the NHT than for the WIN results—the same pattern was observed for both data sets (i.e., as the SNR improved, performance also improved).

Correlations were calculated for the National Hearing Test as a function of three- and four-frequency PTAs, pure-tone thresholds at octave frequencies between 250 Hz and 8,000 Hz, and results of the WIN (in SNR).

There was a positive relationship between three- and four-frequency PTA and NHT results; participants with better hearing were able to perform at a 50 percent NHT level with more noise present (poorer SNR) than were those with poorer hearing, who required quieter conditions to perform at 50 percent. The highest correlations were observed for a pure-tone threshold of 2,000 Hz, three- and four-frequency PTAs, and WIN scores.

Further investigation looked at the effects of whether the NHT was completed at home or in the VA clinic. Of the participants, 188 took the test using their home phone (cell phones were excluded), and 505 took the test at the VA clinic.

Those who took the National Hearing Test at a VA clinic performed better than those who took the test at home. Additional analysis suggested that the at-home test takers were older, had more hearing loss, and showed poorer word recognition than the in-clinic test takers.

The sensitivity and specificity for the NHT were 0.87 and 0.54, respectively, when that measure was compared with the three-frequency PTA, and 0.81 and 0.65, respectively, when compared with the four-frequency PTA. The authors concluded that the National Hearing Test is a valid screening measure of hearing function, and that the test is quick and easy.

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LEADS TO APPROPRIATE REFERRALS

As our clinics face shortages of audiologists and pressure to do more of the complex tasks that we are academically and clinically trained to perform, such as diagnostic testing, hearing aid evaluations and fitting, and cochlear implant evaluations and activations, screening tests that can easily be completed by the patient, require minimal supervision, and have good sensitivity and specificity will become more valuable. The NHT appears to be a tool that results in appropriate referrals for hearing evaluations.

Quick Google searches resulted in 35 million results for “hearing test” and 45 million results for “hearing test online.” Out of curiosity, I took an online hearing test, which used the digits 0 to 9 in noise. I “passed” the test with an 89 percent, whatever that means. Maybe it is my advanced age and poor attending skills that get me into trouble in noise?

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